Well, first you should figure out what kind of Wii you have, as in, does it have a D2A/D2B/D2C chip.
From there, you may or may not decide to continue on your quest for a modchip.
If at all possible, find out if there's a place that mods consoles nearby and check with others to see if it's legit. I know I was more at ease with a professional modding my Wii, especially after seeing what needed to be done with my D2B Wii.
If you have a D2A (Early-ish batch) Wii then it's no harder than soldering a few wires onto a few legs or a quick solder. You just need to make sure nothing is crossing or shorting.
If you have a D2B Wii then 3 of the legs you need to solder are cut and you'll need to sand/grind into the D2B chip to get at the points you need to solder. Screwing this up can potentially wreck your Wii for good, otherwise it's the same as above.
If you have a D2C Wii then you need one of them new-fangled D2C modchips. Last I checked (I stopped checking after I got my modchip.) there was only one modchip available and it required 30 or so wires to solder.
Best of luck whatever you do, the modchip I got has certainly allowed me to try out games I deemed not worth $60. (Cooking Mama looks fun, not $60 fun, same with Mario Party 8 and a ton of others.)
